The invention relates to a screw-in valve comprising a screw-in component, a sleeve with at least two connection openings to which a pressure load can be alternately applied, and a valve piston held for axial displacement in the sleeve for opening and closing a flow connection between the connection openings.
Such screw-in valves are known in various configurations, for example, in the form of directional control valves, check valves or overload valves. The valves can be controlled by hand or by an external force, for example, by means of an electromagnet.
The screw-in valve can be screwed by means of a screw-in component into a housing, for example, a control block, and by axial displacement of the valve piston, i.e., in the longitudinal direction of the sleeve, a flow connection can be selectively opened or closed between two connection openings of the sleeve for a pressure fluid, for example, a hydraulic fluid or compressed air. The axially movable piston is guided in the sleeve with very little play in order to keep leakage of the screw-in valve as low as possible. It has been found that movability of the piston may be impaired by a misalignment of the screw-in component occurring when screwing it into the housing accommodating the screw-in valve. Such a misalignment or canting of the screw-in component cannot always be excluded, as such screw-in valves are often screwed in within a short time under rough ambient conditions by people who are untrained.
The object of the present invention is to further develop a screw-in valve of the kind mentioned at the outset in such a way that the danger of impairing the movement of the valve piston when screwing in the screw-in component is reduced.